The present invention relates to visual task assessment and lighting and environment design. In particular, it concerns evaluating appropriate lighting and environment conditions for conduct of various tasks; and, equipment for conduct of the methods. It also concerns methods and apparatus for conducting visual performance studies, and for implementation of selected lighting designs and programs in the workplace to enhance performance.
Visual performance essential to most industries. It is used, for example, for quality control purposes. In particular, in many industries viewers visually examine materials or manufactured items for defects or appropriate assembly and function. Such visual tasks may be heavily relied upon by the industries involved for maintenance of quality standards and products.
In general, industries have not developed methods of enhancing or optimizing conditions under which such visual tasks are performed. Indeed, in most industries little effort has been made to enhance the conditions under which visual tasks are performed.
In addition, there is a general desire to develop automated systems for replacement of visual inspection by humans. However, for such approaches to be generally successful, it will be necessary to develop methods to define more accurately parameters affecting visual inspection, so that these parameters can then be used to help define automated systems.
It is an object of the present invention to facilitate inspection and viewing processes. This is conducted through the presentation of methods, equipment and environments, for definitions of conditions for preferred conduct of visual tasks, and implementation of preferred visual performance techniques. Many of the principles and techniques described may also be used to facilitate automated processes.
According to the present invention, a method of establishing a lighting system for conduct of a visual task is provided. The method generally includes steps of: providing a visual performance lab; conducting a visual performance study; and, constructing an industrial viewing station based on the conduct of the visual performance study. More specifically, a visual performance lab is provided which includes at least: a viewing station; an arrangement for selectively positioning an object to be viewed and manipulating an orientation and/or distance of the object relative to the viewing station; and, a selectively controlled lighting arrangement. In typical and preferred applications, the selectively controlled lighting arrangement will include at least: an intensity control for selectively modifying an intensity of task light illuminating the object to be viewed; and, a background luminance control for selectively controlling background luminance viewable from the viewing station. Herein the term xe2x80x9ctask lightxe2x80x9d is generally meant to refer to the light source which is dedicated to illuminating the task. For example, in some instances the task light would be a localized light source focused on the task, in others it can be an architecturally mounted light focused more generally on the area in which the task is to be performed or on the object to be viewed.
A variety of arrangements for selectively positioning an object to be viewed and manipulating an orientation of the object relative to the viewing station can be used. In general, the arrangement will be such that an object positioned thereon can be rotated or have its angular orientation selectively modified relative to the viewing station.
In general the step of conducting a visual performance study concerns positioning a viewer at the viewing station and selectively modifying each of selected viewing variables. For example, the variables might be the orientation of the object being viewed, the intensity of task light illuminating the object being viewed, the background luminance, masking light luminance, light color or light angle. The visual performance study is generally conducted to determine preferred values for the variables, for example preferred orientation, task light intensity and background luminance for viewing the object. Herein the term xe2x80x9cpreferredxe2x80x9d in this context is meant to refer to the favored selected value of the observer(s) at the viewing station. The term xe2x80x9cpreferredxe2x80x9d is not meant to necessarily refer to a specific mathematical optimum, but rather is intended to be a narrative preference indication. That is, if the viewer is a human, the preferred value is the value for a variable indicated by that person as preferred for his or her viewing of the task. In some instances, the xe2x80x9cpreferredxe2x80x9d value may be a range of values. If the observer is an automated system, the xe2x80x9cpreferred valuexe2x80x9d is typically the value at which detection/differentiation is xe2x80x9cbestxe2x80x9d performed by the system.
The step of constructing an industrial viewing station for the object, based upon the visual performance study, is generally conducted by creating a viewing station for viewing objects, and providing at the viewing station illumination of the task or task object by using equipment that can be controlled to implement the preferred values obtained by conducting the visual performance study. For example, if a preferred intensity of task light is identified in the visual performance study, the step of constructing the industrial viewing station would include a step of providing lighting equipment selectively adjustable to provide that intensity. Other variables such as background luminance, color, angle of illuminating task light, amount of masking light, etc. may be involved as well.
In some preferred arrangements, the construction or arrangement for selectively positioning the object to be viewed may be a goniometer. However, a wide variety of equipment generally may be utilized for this purpose.
In some instances, the visual performance study may generally be conducted by: serially positioning members of a selected population of viewers at the viewing station; and, determining each viewer""s preferences with respect to lighting and positioning variables in the preferred lighting condition. The information can then be assimilated to develop preferred ranges of values for implementation in the industrial viewing station, in a preferred lighting condition. In typical studies, with respect to each variable, a viewer will likely be identified who is the xe2x80x9cleast visually capablexe2x80x9d with respect to that variable. It will often be the case (with respect to implementing a preferred condition with respect to that variable in an industrial viewing station) that the preferred value selected will be that person""s preference, as the xe2x80x9clowest common denominatorxe2x80x9d for the relevant population with respect to that particular variable. For example, suppose in the test population a range of preferred intensities is found. In general, what will be selected for implementation will be the intensity at which the least visually capable viewer (with respect to intensity) could adequately perform the task. This type of implementation will help ensure that the task can be appropriately performed by any of a variety of viewers, in the field.
Also according to the present invention a visual performance lab is provided. In general, the preferred visual performance lab includes appropriate equipment for conduct of the study described above.
In addition, according to the present invention various industrial viewing stations are provided. In general, these stations will include equipment appropriate to implement the preferred lighting conditions identified by the lab study. In some instances, it will be preferred to provide equipment that is selectively adjustable to implement more than one lighting condition for preferred viewing. Typically, a visual surround will be included, to block outside light from reaching the viewing station; and, the visual surround will include a luminous surface, such as a grid, directed toward objects to be viewed.